Upfront EGFR TKI with or without brain radiotherapy (RT) in EGFR-driven non-small cell lung cancer (NSCLC) with brain metastases.

Abstract

e20614 Background: The central nervous system (CNS) remains a common site of metastatic disease for NSCLC, especially in EGFR-driven disease. Surgery and RT are upfront treatment options but have potential early and late onset complications. Osimertinib (Osi) is now approved for use in the front-line setting for EGFR-mutated NSCLC and is highly CNS penetrant. A prior retrospective study showed that the use of early generation EGFR TKIs had an inferior overall survival (OS) compared to upfront RT in newly diagnosed brain metastases, but the applicability of this data in the Osi-era is unknown. Methods: This was a single institution retrospective analysis of patients with EGFR mutated NSCLC and brain metastases who were referred to Radiation Oncology from 1/1/2012 to 12/31/2018. We separated EGFR TKIs between Osi and non-Osi. The primary objectives were to evaluate OS, intracranial progression free survival (icPFS), and intracranial response (icORR) among upfront or delayed RT, and type of EGFR TKI. Results: 67 patients with a median age of 64 years old (33-89) were divided into one of four groups: non-Osi TKI with (N = 38) or without RT (N = 12), and Osi with (N = 14) or without RT (N = 3). Fourteen patients who did not get upfront Osi, received Osi with (N = 7) or without RT (N = 7) after intracranial progressive disease (icPD). Patients were predominantly female, never-smokers, and with an ECOG PS 0-1. Brain metastases were mostly asymptomatic and < 10 mm. The OS for the entire population was 26.7 months (95% CI, 23.9-29.5); there was no difference between groups, and use or type of RT versus TKI. The icPFS was 14.3 months (95% CI, 9.1-19.5), icORR was 64.2%, and icDCR was 82.7%, without any difference between groups. Among those patients who did not receive upfront Osi, use in the post-progression setting resulted in a significantly longer OS (54.8 vs. 23.0 months, p = 0.001). Conclusions: We found no statistical difference in OS, icPFS, or icORR in patients treated with upfront RT or EGFR TKI. Results should be confirmed with a prospective study.